Electronic control device

Abstract

Provided is an electronic control device, including: a plurality of grounding terminals provided to a plurality of grounds in the device individually on a one-to-one basis; a grounding common portion for connecting a plurality of grounding points provided to the plurality of grounds individually on a one-to-one basis; a current detection unit configured to detect each of currents flowing between the plurality of grounding points and the plurality of grounding terminals provided for the plurality of grounding points individually on a one-to-one basis or a current flowing through the grounding common portion; and a controller configured to detect a ground open condition for each of the plurality of grounds by comparing a detection result obtained by the current detection unit with a determination value for determining the ground open condition.

The invention claimed is: 
     
       1. An electronic control device, comprising:
 a plurality of grounding terminals provided to a plurality of grounds in the electronic control device individually on a one-to-one basis; 
 a grounding common portion for connecting a plurality of grounding points provided to the plurality of grounds individually on a one-to-one basis; 
 a current detector configured to detect each of currents flowing between the plurality of grounding points and the plurality of grounding terminals, respectively, or a current flowing through the grounding common portion; and 
 a controller configured to detect a ground open condition for each of the plurality of grounds by comparing a detection result obtained by the current detector with a determination value for determining the ground open condition, 
 wherein the electronic control device further comprises a plurality of circuit groups provided for the plurality of grounding terminals individually on a one-to-one basis, 
 each of the plurality of circuit groups includes:
 a microcomputer, and 
 a driver connected to a corresponding grounding point and configured to drive a target device under control of the microcomputer, and 
 
 the controller is formed of respective microcomputers of the plurality of circuit groups. 
 
     
     
       2. The electronic control device according to  claim 1 , wherein the current detector is formed of a plurality of current detectors provided for the plurality of grounding terminals individually on a one-to-one basis, and
 the plurality of current detectors are configured to respectively detect the currents flowing between the plurality of grounding points and the plurality of grounding terminals. 
 
     
     
       3. The electronic control device according to  claim 1 , wherein the current detector is formed of one current detector provided for any one of the plurality of grounding terminals, and
 the current detector is configured to detect any one of the currents flowing between the plurality of grounding points and the plurality of grounding terminals. 
 
     
     
       4. The electronic control device according to  claim 1 , wherein the current detector is formed of one current detector provided to the grounding common portion, and
 the current detector is configured to detect the current flowing through the grounding common portion. 
 
     
     
       5. The electronic control device according to  claim 1 , wherein the current detector includes a resistor. 
     
     
       6. The electronic control device according to  claim 5 , wherein the resistor is formed as a part of a bus bar. 
     
     
       7. The electronic control device according to  claim 6 , wherein the resistor has a U-shape. 
     
     
       8. The electronic control device according to  claim 5 , wherein the resistor includes a shunt resistor. 
     
     
       9. The electronic control device according to  claim 1 , wherein the current detector is configured to detect a current from a magnetic field generated by the current. 
     
     
       10. The electronic control device according to  claim 1 , wherein the plurality of grounding points includes a first grounding point and a second grounding point,
 the plurality of grounding terminals includes a first grounding terminal and a second grounding terminal, and 
 an impedance between the first grounding terminal and the first grounding point and an impedance between the second grounding terminal and the second grounding point are matched. 
 
     
     
       11. The electronic control device according to  claim 1 , wherein the controller is configured to learn a current value detected by the current detector when the target device is not in operation, and change the determination value based on the learned current value. 
     
     
       12. An electronic control device comprising:
 a plurality of grounding terminals provided to a plurality of grounds in the electronic control device individually on a one-to-one basis; 
 a grounding common portion for connecting a plurality of grounding points provided to the plurality of grounds individually on a one-to-one basis; 
 a current detector configured to detect each of currents flowing between the plurality of grounding points and the plurality of grounding terminals, respectively; and 
 a controller configured to detect a ground open condition for each of the plurality of grounds by comparing a detection result obtained by the current detector with a determination value for determining the ground open condition, 
 wherein the current detector is formed of a plurality of current detectors provided for the plurality of grounding terminals individually on a one-to-one basis, 
 the plurality of current detectors are configured to respectively detect the currents flowing between the plurality of grounding points and the plurality of grounding terminals, and 
 the current detector includes a resistor formed as a part of a bus bar. 
 
     
     
       13. The electronic control device according to  claim 12 , wherein the resistor has a U-shape. 
     
     
       14. The electronic control device according to  claim 12 , wherein the resistor includes a shunt resistor. 
     
     
       15. The electronic control device according to  claim 12 , further comprising a plurality of circuit groups provided for the plurality of grounding terminals individually on a one-to-one basis,
 each of the plurality of circuit groups includes:
 a microcomputer, and 
 a driver connected to a corresponding grounding point and configured to drive a target device under control of the microcomputer, and 
 
 the controller is formed of respective microcomputers of the plurality of circuit groups.